This is battlefield. Vehicles are part of Battlefield. Adapt.
Tanks require 2 RPGs to kill (if you hit them from behind, which is what you should do). If tanks make it to final circle, that is your lobbies fault for not dealing with the high priority threat. There are other methods that would work as well, like the various mines, which become more of a threat when the tank has less room to maneuver. So, bring an engineer, it comes with rockets to start (and repair tool can destroy a tank).
There also are airstrikes and artillery; which you can save for armor, instead of firing them off when you get a whiff of an enemy on the horizon (like I see so many players do).
Also, nothing stops your squad from trying to get tanks as well; if you think they are that powerful, get them yourself (and you will quickly find out when you come up against a veteran BF engineer, that tanks are not that hard to deal with yourself).